Questions and Answers

Answers to Lecture Learning Objectives – Full Sentences

Describe and compare the concepts of parental investment and parent–offspring conflict.

Parental investment is any effort by a parent to increase an offsprings chance of survival at the cost of the parents ability to invest in other offspring or future reproduction.

Parent-offspring conflict arises because offspring beenfit from more care to themselves, while parents must distribute care to all other offsproing and future reproduction. An example is in the soft smooth-shelled turtle, where offspring benefit from larger eggs, but parents maximise their fitness by producing many smaller eggs.

Evaluate the signal-of-need vs signal-of-quality hypotheses using real-world examples.

The signal-of-need hypothesis states that begging intensity reflects the hunger of an offspring and encourages parents to feed the neediest chick. This is more common when food is abundant and promotes equla food distribution among siblings.

The signla-of-quality hyptohesis states that displays shows the intrinsic condiiton or viability of an offspring nad encourages parents to feed the high quality chick when resources are scarce. An example of this is the barn swallow gape colour experiment where red-painted gapes received more food despite equal hunger, which supports the signal of quality hypothesis.

Analyse how sibling competition over parental investment can lead to extreme behaviours such as siblicide, and evaluate the ecological drivers of such behaviours.

Sibling competition can escalate to siblicide when resources are limited. Obligate siblicide always occurs, as in the Nazca boby, while facultive siblicide only occurs under scarcity, as in the blue-footed booby. Ecological drives of siblicide are food availability, parental intervention, and environmental changes which influence whether the weaker chick can surivive.

Explain the concept of brood parasitism and analyse the coevolutionary arms race between brood parasites and their hosts, using cuckoos as a case.

Brood parasitism is when one species lays its eggs in another species nest, forcing the host to care for its offspring.

Hosts evolve adaptations such as egg rejection, nest defence, and chick recognition to reduce the success of parasites.

Parasites evolve counter-adpatations such as egg mimicry, rapid egg laying, chick mimicry, and ‘password’ calls. This reuslts in an ongoing coevolutionary arms races between hosts and parasites.

Explain the biological distinction between sex and the sociocultural construct of gender, and discuss how this distinction is relevant in studies of animal behaviour.

Sex is a biological category based on characteristics like chromosomes, gamete, and anatomy. Gender is a human sociocultural idnetity and set of roles. In animal behaviour studies, researchers use the term sex rather than gender to describe the reproductive categories and avoid anthropomorphic confusion.

Analyse how anisogamy and Bateman’s principle shape patterns of sexual selection, including why males often compete and females are typically the choosy sex.

Anisogamy refers to the difference in gamete size between males and females, where females produce few large gametes and males produce many small gametes. Batemans principle states that males reproductive success increases with the number of mates, whereas female reproductive success plateaus after the first fertilisation. This difference means that males often compete for access to females, while females are typically mroe choosy in selecting mates.

Define and distinguish between intersexual and intrasexual selection, and illustrate each with relevant animal examples.

Intersexual selection is mate choice between sexes. An example is in female pronghorns choosing mates with stronger endurance disaplys. Intrasexual selection is competition withing one sex. For example, male-male combat in African buffalos.

Differentiate between alternative mating tactics and alternative mating strategies, and evaluate their adaptive significance.

Alternatve mating tactics are flexible, condition-dependent behaviours used by males that are not dominant, such as the small male giraffe weevils sneaking copulations.

ALternative mating strategies are genetically fixed morphs with equal fitness over time, such as the throat colour morphs in side-blotched lizards.

Both types allow individuals to reproduce successfully in changing environments.

Analyse the conditions under which sex-role reversal and female competition evolve, particularly when males are scarce and choosy.

Sex-role reversal occurs when males provide extensive parental care, which makes them a limiting resources for reproduction. When males are scarce and choosy, female soften compete for mates. An example is the pipefihs, where males carry embryos and females dispaly ornaments to attract them.

Evaluate the causes and consequences of sperm competition, and compare male adaptations to engage or avoid sperm competition, using examples.

Sperm competition occurs when femlaes mate with multiple males. Male adpatations to engage in sperm competition are larger testes and more sperm, as in dubg beetles, and faster sperm as seen in rodents. Adaptations to avoid sperm competition are mate guarding seen in giraffe weevils, mating-plugs in spides, and receptivity-reducing proteins in drosophila. These traits influence reproductive success and can drive evolutioanry change.

Describe and compare the potential benefits of polyandry for females, using examples to illustrate both direct and indirect fitness benefits.

Direct benefits of polyandry include fertility assurance, resources such as nuptial gifts as in mormon crickets, and nutrients from esuxal cannabilism in fishing spiders. Non-direct benefits are higher viability of offspring through good genes, increased genetic diversity as in honeybee colonies, and greater immune system compatability as in sand lizards with diverse MHC genes.

Be able to define the main animal mating systems and give examples of each.

Monogamy is when one male mates with one female, as in californian mice.

Polygyny is when one male mates with multiple females, as in sage grouse leks.

Polyandry is when one female mates with mupltiple males, as in norhtern jacannas.

Polygyandry is when both sexes mate with multiple partners but maintain semi-stable pair bonds, as in bonobos.

Promiscuity is when both sexes mate with multiple partener and have no stable pair bond, as seen in many fish species.

Be able to describe and compare theories for why some species are monogamous, using examples.

The mate guarding hypothesis suggests that males stay with one female to prevent rivals from mating with her, as in hulagin shrimp.

The mate assistance hypothesis states that male carae increases offspring survival, as seen in californian mice during cold conditions.

The female-enforced hyptohesis describes that females prevent males from attracting other mates, as in burying beetles.

Explain the difference between genetic vs social monogamy and what extra-pair copulations are.

Social monogamy is when a pair bond is observed, but the genetic offspring may come from other mates.

Genetic monogamy is when all offspring come from the same pair.

Extra-pair copulations are matings outside the primary pair bond, which can result in extra-pair paternity.

Compare the potential costs and benefits of extra-pair copulations for males and females.

For males, the benefits include many offspring, while the costs include the loss of paternity in their own nest. For females, benefits include good genes and fertility insurance, while costs include the risk of mate desertion, aggression, and disease.

Discuss the ethical views associated with animal research.

Utilitarianism weighs the harms against the benefits and aims to maximise overall welfare.

Deontology holds that some actions are morally wrong regardless of potential benefits.

Virtue ethics focuses on the character of the researcher and the importance of humane intentions.

Relational ethics, including Kaupapa Māori, emphasise relationships, respect, and values such as tikanga, mauri, and whakapapa.

Explain the importance of ethical accountability for animal behaviour research.

Ethical accountability ensures animal welfare, maintains public trust, meets legal and institutional requirements, and avoids unnecessary harm or suffering.

Explain the use of the Three Rs in animal behaviour research.

Replacement means using non-animal methods where possible.

Reduction means minimising the number of animals used without reducing the quality of results.

Refinement means improving methods to reduce pain, stress, or suffering for the animals involved.